1. Field of the Invention
This invention generally relates to apparatus for supporting loads and more particularly to apparatus for supporting loads in a cargo box, such as found in pickup trucks with wheel wells protruding into the cargo box.
2. Description of Related Art
In recent years pickup trucks have replaced full-size trucks for the transportation of goods and materials, especially those used in construction. Pickup trucks are less expensive to purchase and operate and have a smaller overall profile than full-size trucks. A reduction in width has been made possible by moving the wheels inwardly toward the center line of the truck and fashioning wheel wells within a cargo box to cover the wheels.
Although the top of such a cargo box may have an opening in excess of four feet, the standard width of many construction materials such as plywood and wallboard, the clearance on the floor between the wheel wells is less. It is not possible to store construction panels horizontally on the floor. Vertical storage is not always acceptable because the edges of the panels can be damaged and the center of gravity of the load can rise two feet above the floor making the load less stable during transportation. Moreover, special structures must stabilize the load, and it is difficult to cover vertical panels to protect them from weather and vandalism.
The inability to carry panels on the floor of a cargo box in pickup trucks has led to structures for adapting the cargo boxes for storing panels and other oversized items. Suggestions for adapting cargo boxes of pickup trucks with internal wheel wells for receiving such items are disclosed in the following patents:
U.S. Pat. No. 2,697,631 (1954) Miller PA1 U.S. Pat. No. 4,215,898 (1980) Ulics PA1 U.S. Pat. No. 4,394,100 (1983) Sperlich PA1 U.S. Pat. No. 4,527,827 (1985) Maniscalco et al PA1 U.S. Pat. No. 4,751,981 (1988) Mitchell et al
The Miller patent discloses a structure for engaging a flange on a cargo bay and a depending channel. Opposed channels receive vertically stacked boards to form a partition that separates the cargo bay into separate components. In one embodiment a curved upper edge portion of a support structure engages outwardly rolled marginal portions or flanges of a cargo bay side wall. A vertically extending channel lies inside a cargo bay against a side wall and receives the transversely extending boards to provide the transverse vertical partition. As the boards are placed in the opposed channels, they force the channels outwardly into clamping engagement with side walls.
The Ulics patent discloses a modification to a conventional pickup truck with internal wheel wells. Preformed recesses, produced during manufacture or by structural modification to the vehicle and located in side walls, support transverse beams. The beams define a support surface or load support plane for such construction panels and the like. The plane lies at or above the upper plane of the wheel wells.
Sperlich discloses a structure for supporting a horizontal panel as a cover that includes a channel across the front wall of a cargo box and another channel in a tailgate. The channels lie in a plane corresponding to a plane through horizontal treads at the top of internal wheel wells. The channels support the ends of a covering panel. The treads support the panel at an intermediate position along the panel side. Affixing channels to the front end of the cargo bay and to the tailgate constitutes a structural modification. Moreover, a panel supported only at the ends and at the treads is not adapted for supporting heavy loads.
Maniscalco et disclose a support structure that clamps to the flanges of a cargo box for supporting a load element that is larger than the cargo box and defines a horizontal support surface that lies above the cargo box. Particularly Maniscalco discloses a vertical rack for windsurfing boards with a horizontal support that is elevated above the cargo box by inclined legs that clamp to flanges at the cargo box and the horizontal support member. The height of the support surface makes it difficult to load and unload heavy items, such as construction panels, from the support.
Mitchell et al disclose a ladder rack that is removable from the cargo box. The ladder rack has a support structure bolted to the sides of the cargo box and a ladder support structure with vertically disposed stanchions that engage the brackets. Mitchell et al require structural modifications to the vehicle.